Roofing Material Calculator
Worked example result
| Flat (plan) area | 1,200 sq ft |
| Sloped roof area | 1,342 sq ft |
| Squares (exact) | 13.42 |
| Squares to order | 14 |
| Shingle bundles (3 per square) | 42 |
| Underlayment rolls | 4 |
A 40 × 30 ft roof plan is 1,200 sq ft; at a 6/12 pitch (×1.118) the sloped area is 1,342 sq ft = 13.42 squares. Order 14 squares: 42 shingle bundles and 4 rolls of underlayment.
Roof area = Length × Width × pitch multiplier; Squares = Area ÷ 100; Bundles = ceil(Squares) × 3; Rolls = ceil(Area ÷ 400) · Powered by CalcHub — Roofing Material Calculator